The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
System controls for machines, such as motor vehicles, airplanes, industrial equipment, etc., include an interface device used by an operator of the machine to control the operation of the machine. These interface devices may include knobs, switches, levers, etc. A mechanical linkage may connect the interface device to the mechanism being controlled or a human machine interface (HMI) system may be used where an electromechanical interface device is in electronic communication with the mechanism to be controlled. In HMI systems the mechanical movement of the electromechanical interface device is translated into an electrical signal that is communicated to the controlled mechanism.
In both cases it is important that the interface device provide proper “feel” to the operator in order to denote specific operating positions. For example, a traditional shift control for a motor vehicle may include a shift lever mechanically linked to a transmission through a shift cable. As the shift lever is moved, the cable transmits the movement to the transmission which in turn engages different gear or operating states, such as park, neutral, drive, etc., based on this transmitted movement. In shift-by-wire systems the shift cable between the shift lever and the transmission is eliminated and instead movement of the shift lever sends a control signal to the transmission which then, based on the control signal, engages the desired gear or operating state. In both cases it is desirable to provide non-visual feedback to the user when each of the operating positions (i.e., park, neutral, reverse, drive) has been achieved.
One solution is to use a mechanical feedback mechanism having a wheel, a roller and a torsion spring to generate the required feel. While these mechanisms are useful for their intended purpose, they are inherently tailored to the specific mechanism being used. For example, a vehicle with gear positions of park, neutral, reverse, and drive while another vehicle with gear positions of park, neutral, reverse, drive, and manual will need two different mechanical feedback mechanisms in order to accommodate the additional (manual) gear selection. Adding additional parts to the mechanical feedback mechanism may require new tooling, testing on the part, testing on the sample, and testing on the vehicles, and may require new position sensors for the modified part.
One solution is to provide electromechanical feedback mechanisms that replace some of the mechanical parts of the mechanical feedback mechanism with electrically controlled mechanism. While these mechanisms are useful for their intended purpose, the electromechanical interface devices may provide a diminished user experience due to the lack of a “mechanical feel” to the device. This lack of mechanical feel is greatly compounded when the interface device is moved or operated quickly. And yet, this mechanical feel is important for tactile feedback to an operator of the electromechanical interface. Thus, there is a need in the art for an electromechanical interface device that provides sufficient tactile feedback to an operator of the device under all operating conditions and that can be used in various configurations without requiring additional mechanical parts and redesigns.